Up and Under...and Steady As It Goes

On this project connecting Norfolk and Portsmouth, Virginia, USA, the construction of a second Midtown Tunnel under the Elizabeth River included relocating an existing 36” water main to make room for the new tunnel.

The Elizabeth River Tunnels Project is a Public Private Partnership between the Virginia Department of Transportation and Elizabeth River Crossings Operating Company. SKW Constructors, A Joint Venture of Skanska, Kiewit and Weeks Marine, is the design-build contractor. The horizontal directional drilling work was awarded by SKW Constructors to the Michigan-based Mears Group, a recognized specialist as one of the largest HDD contractors in the world.

The project includes a new 36” line beneath the Elizabeth River. Work on the pipe itself, including its fabrication, coating, testing and handling was carried out by Patterson & Wilder Construction Co. as a subcontractor to Mears, with Virginia-based McClung-Logan as the servicing dealer.

Assembling the pipeline

The first step in the project was to assemble a 60” diameter casing through which the drill would pass, followed by the assembly of the pipe itself, comprising 4,500’ of 36” diameter pipe. The pipe had to be strung out, the tie-ins completed and then, using cranes and pipelayers, the pipe had to be lifted to the drilling rig to line it up with the orientation of the drill stem in order for the pipe to be pulled all the way under the river.

Normal work, but not really average

“We consider this normal work, but not really average,” said Ed Kosarek, VP for field operations with Patterson & Wilder. “This is a fairly large project in terms of length and diameter and with some of the environmental concerns involved in drilling under a river. We don’t want any kind of environmental hazard.”

With the pulling forces exerted on the different machines, Patterson & Wilder wanted to ensure that their capacity exceeded the requirement by at least 50% to ensure that the whole operation be safe and successful.

“In today’s economy,” continued Ed, “that’s the name of the game. You have to get it done smarter, quicker and safer. If you don’t capture all that within your project, you’re not going to succeed.”

The Volvo PL4608 rotating pipelayer

“The major difference between a Volvo pipelayer and one of their major competitors,” explained Ed Kosarek, “is the fact that the Volvo pipelayer is actually a rotating pipelayer. The tracks can stay stationary, but the whole cab and boom of the machine can rotate. There’s no other pipelayer that can do that and that’s really what turned us towards the Volvo in this situation. It’s just a much more versatile machine for this application.”

In addition to the unique, 360° swing capability, the hydraulically elevating cab on the PL4608 can significantly improve operator visibility for increased site safety.

Patterson & Wilder’s involvement in this project was about three months, from mobilization to demobilization. Work on the tunnel itself is scheduled for completion in 2016.